The Monterey Bay Aquarium (www.mbayaq.org) is world famous. I remember my visit from 20 years ago as exceptional and it has not changed. The Star Trek movie where they rescue the whales was filmed there and it is neat to recognize all the scenery as an added extra.
Wonderful living displays in tanks up to 1 million gallons, in a working seaquarium. We saw feeding time activity for various species and even got to touch a Manta Ray (like wet velvet).
A great 6 hours. We could have done more but our feet gave out.
Then we took the scenic 17 mile drive through the Pebble Beach and other golf clubs area on the beach. Incredibly fine, white sand beaches and shore, backed by the golf courses and stunning sea front homes. At one beach we saw the sea otters playing and feeding in the wild, just after seeing them close at the Aquarium. Similarly Harbour Seals.
Finished a great day but finding some dinner and back to the hotel (and a little internet)…